1. Field of the Invention
The present invention relates to a recording tape cartridge. More particularly, the present invention pertains to a recording tape cartridge in which a single reel on which is wound a recording tape such as a magnetic tape usable as a recording and reproducing medium for a computer or the like is accommodated in a case.
2. Description of the Related Art
There has heretofore been known a recording tape cartridge in which a recording tape such as a magnetic tape usable as a recording and reproducing medium for a computer or the like is wound on a reel, and the reel is rotatably accommodated in a case formed from a plastic material. The recording tape cartridge is arranged such that when in use (when loaded into a drive device), the reel is rotatable in the case, while when in non-use, the reel is locked so as to be non-rotatable in the case.
More specifically, the recording tape cartridge includes brake means for preventing the reel from being rotated within the case when the cartridge is in non-use. The brake means may be constructed such that a brake member, which for example is non-rotatable with respect to the case, can be engaged with the reel.
As shown in FIG. 8, for example, a brake member 130 is configured in the form of a disk which is disposed in such a manner as to be vertically movable within a bottomed, generally cylindrical shape reel hub 112 of a reel 110. A pair of engagement projections 134 which define a U shape as seen in a plan view are provided upright on the upper surface of the brake member 130. A pair of rotation regulating ribs 126 depending from the inner surface of an upper case half 122 are inserted inside the engagement projections 134, thereby making the brake member non-rotatable with respect to the case.
Further, the brake member 130 is normally biased toward a bottom wall 114 of the reel hub 112 with the aid of a biasing member such as compression coil spring 116, so that an annular brake gear 132 formed in the lower surface of the brake member 130 is meshed with an annular engagement gear 118 formed in the upper surface of the bottom wall 114 of the reel hub 112. In this manner, the reel 110 is prevented from inadvertent rotation.
Still further, a generally cylindrical operation projection 136, which is projectingly provided at an axial center portion of the brake member 130, is inserted in a through hole 114A formed in an axial center portion of the bottom wall 114 of the reel hub 112, and exposed through a gear opening 128 formed substantially at a center portion of a lower case half 124. In an attempt to make the reel 110 rotatable, the operation projection 136 (brake member 130) is pushed upward, and as a result the brake gear 132 is disposed out of engagement with the engagement gear 118 (refer to U.S. Pat. No. 6,452,747, for example).
However, with the above-described arrangement, since the reel 110 is movable upward (movable axially of the reel 110) against a biasing force of the biasing member such as compression coil spring 116, it is likely that in case the bottom wall 114 of the reel hub 112 is moved upward because of the recording tape cartridge being impacted due to dropping or the like, the brake member 130 becomes tilted and jammed at the edge of the through hole 114A while being in a tilted orientation (being on the point of falling) as shown in the drawing.
If the recording tape cartridge is loaded into a drive device under such a condition, there tends to arise a problem that not only the recording/reproducing operation cannot be performed but also the recording tape cartridge is damaged or the drive device malfunctions. Another problem is that since the reel becomes rotatable when in non-use, the recording tape tend to get wrinkled or torn off.